This invention relates to methods for inhibiting, preventing, protecting against or treating the deleterious effects of reactive oxygen species. The invention also relates to methods for protecting against injury to tissues from ischemia and reperfusion injury.
Superoxide radicals (O.sub.2.sup.-) and other highly reactive oxygen species such as hydrogen peroxide (H.sub.2 O.sub.2) and hydroxyl radicals (referred to herein as reactive oxygen species or "ROS") are produced in vivo by enzymatic, spontaneous, and photochemical oxidation reactions. ROS are produced by mitochondria during electron transport. Other intracellular sources of O.sub.2.sup.- and H.sub.2 O.sub.2 are endoplasmic reticulum, peroxisomes, and nuclear and plasma membranes. Examples of disorders associated with the generation of ROS include: synovial inflammation induced by bacterial lipopolysaccharide endotoxin (LPS), inflammation caused by adjuvant-induced arthritis, bleomycin-induced lung fibrosis, reperfusion injury, transplantation rejection, hyperoxia, and any diseases caused by light. It has been suggested that ROS may be involved in hyperthermic cell injury (Omar et al., Cancer Res. 47:3473, 1987), and that thermosensitivity is linked to a low rate of free radical removal.
Certain agents are capable of inducing superoxide or other oxygen free radicals. Such ROS activity may be determined by commonly used methods, such as their ability to induce guinea pig alveolar macrophages to produce reactive oxygen metabolites which are measurable by spectrometer at A.sub.550-540 nm (Leurs at al., Biochemistry International 18 (2):295-299, 1989), or by known inflammatory or chemiluminescence test models. Agents which are known to enhance the production of ROS include but are not limited to the following commercially available compounds: inhibitors of glutathione synthesis such as buthionine sulfoximine, anthracyclines such as adriamycin (doxorubicin), adriamycinone (doxorubicinone), daunomycin, daunomycinone, daunorubicin, and daunorubicin derivatives such as 5-iminodaunorubicin, ubiquinone, Acid Blues 25, 80, and 41, Acid Green 25, anthraquinone and its derivatives such as 2-bromoanthraquine, 1,2-dihydroxyanthraquinone, 1,8-diaminoanthraquinone, 2,6-diaminoanthraquinone, 1,5-dichloroanthraquinone, 1,2-diaminoanthraquinone, and 2-chloro-anthraquinone, quinizarin, anthrarufin, quilalizarin, aloe-emodin and related compounds such as 5-nitro-aloe-emodin, 5-amino-aloe-emodin, 2-allylaloe-emodin, averufin, kalafungin, alizarin complexone dihydrate, quercetin dihydrate, acid black 48, procytoxid, leucotrofina, azimexon, and methoxycin-namonitrile. These ROS inducing agents may be administered therapeutically, by intravenous or other methods as desired.
A group of metalloproteins known as superoxide dismutases (SOD) catalyze the oxidation-reduction reaction 20.sub.2.sup.- +2 H.sup.+ .fwdarw. H.sub.2 O.sub.2 +O.sub.2 and thus provide part of the defense mechanism against oxygen toxicity. Eukaryotic cells contain copper-zinc SOD, which is found predominantly in the cytosol, and MnSOD, which is found mainly in mitochondria. Extracellular SOD is found primarily in extracellular fluids such as plasma, lymph, and synovial fluid, but occurs also in tissues (Hjalmarsson et al., Proc. Natl. Acad. Sci. USA 84:6340, 1987).
The scientific literature suggests that SOD administration may be useful in a wide range of clinical applications. Potential applications include prevention of oncogenesis and of tumor promotion, treatment of inflammations, reduction of the cytotoxic and cardiotoxic effects of anticancer drugs, protection of ischemic tissues and protection of spermatozoa (EPO Appl. EP 0 284 105 A2). It has also been suggested that oxygen free radicals are involved in the pathogenesis of, and that SOD administration protects against, influenza virus infection (Oda et al., Science 244: 974-976, 1989).
Ischemia causes injury to cells, and if continued for a sufficient length of time, can kill them. Reperfusion after a brief period of ischemia, although beneficial in the long term, frequently results in an initial injury to the tissues upon reoxygenation, presumably through the formation and involvement of reactive oxygen species. This phenomenon has been described in the literature with heart, skin, intestine, pancreas, and variety of tissues. It is also important to protect against reoxygenation injury during thrombolytic therapy, and in the preservation of organs for transplantation.
Tumor necrosis factors (TNFs) are polypeptides produced by mitogen-stimulated macrophages (TNF-.alpha.) or lymphocytes (TNF-.beta.) which are cytotoxic to certain malignantly transformed cells but not to certain normal cells (E. A. Carswell et al., Proc. Natl. Acad. Sci. U.S.A. 72:3666, 1975; B. J. Sugarman et al., Science 230:943, 1985; Schutze et al., J. Immunol. 140: 3000, 1988). TNF-.alpha. has been suggested to be responsible for wasting and cachexia in patients with cancer or severe infections, and both TNF-.alpha. and TNF-.beta. mediate many other biological effects. TNF is also known to induce MHC antigens. The inventors herein have reported that TNF induces MnSOD in various transformed and normal cell lines (Wong et al., Science 242:941, 1988).
TNF at certain dosages is known to trigger the generation of ROS in macrophages or neutrophils (Tsujimoto et al., Biochem. Biophys. Res. Commun. 137:1094, 1986; Matsubara et al., J. Immunol. 137:3295, 1986; Shalaby et al., Leuk. Biol. 41:196, 1987; Berkow et al., J. Immunol. 139:3783, 1987). It has been suggested repeatedly in the literature that TNF at certain dosages enhances tissue injury caused by reactive oxygen species (see, e.g. Clark et al., J. Cell Biochem. Suppl. 12A, p. 40, Jan 1988; Sullivan at al., Infect. and Immunity 56(7): 1722-1729, 1988; and Tiegs at al., Biochem. Pharmacol. 38(4): 627-631, 1989).
The literature has reported that TNF-.alpha. and other cytokines such as IL-1 may protect against the deleterious effects of ionizing radiation produced during a course of radiotherapy, such as denaturation of enzymes, lipid peroxidation, and DNA damage (Neta et al., J. Immunol. 136(7):2483, 1987; Neta et al., Lymphokine Res. 5(1):5105-110 (1986) Neta et al., Fed. Proc. 46:1200 (abstract), 1987; Urbaschek et al., Lymphokine Res. 6:179, 1987; U.S. Pat. No. 4,861,587; Neta et al., J. Immunol. 140:108, 1988), and that TNF treatment accelerates restoration of hematopoiesis in animals compromised by sublethal doses of cytotoxic drugs or irradiation (Neta, et al., Blood 72(3):1093, 1988). A recent article reported that pretreatment with TNF protects mice from lethal bacterial infection (Cross et al., J. Exp. Med. 169:2021-2027, 1989). It has also been suggested that administration of subdeleterious amounts of TNF and/or IL-1 may modulate the deleterious effect of subsequent TNF and/or IL-1 administration; this reference further suggests that ionizing radiation may be administered as a sensitizing agent (EPO Appl. EP 0 259 863 A2). It has also been reported that pretreatment of cells with low levels of either TNF or IL-1 can confer resistance to killing by subsequent treatment with TNF-.alpha. and cycloheximide in combination (Wallach, J. Immunol. 132:2464, 1984; Hahn et al., Proc. Natl. Acad. Sci. U.S.A. 82:3814, 1985; Holtmann et al., J. Immunol 139:1161, 1987). It has been suggested that inadequate endogenous levels of TNF may be involved in the development of lupus erythematosus (Jacob et al., Nature 331:356-358, 1988).
It is an object of this invention to provide methods for protecting ischemic tissues, such as those tissues, bones or organs to be transplanted from a donor to a recipient patient, or those tissues whose oxygen supply has been blocked, from the effects of ROS.
It is a further object herein to provide methods to inhibit, prevent or treat reperfusion injury, bronchopulmonary dysplasia, stroke, arteriolosclerosis, atherosclerosis, myocardial infarct, inflammatory autoimmune diseases, viral infection, inflammation-induced arthritis, hyperoxia, sepsis, diabetes, influenza, multiple sclerosis, premature birth, acquired immunodeficiency syndrome, transplant rejection or transplantation injury, bleomycin-induced lung fibrosis, synovial inflammation induced by bacterial LPS endotoxin, lung injury resulting from immune complexes, kidney disease, Parkinson's disease, sickle cell anemia, sickle cell trait, alcoholic or non-alcoholic cirrhosis, or other diseases associated with toxic ROS.
Another object of this invention is to supply perfusion solutions and excised, perfused tissues for transplant.
These and other objects of the invention will be apparent from consideration of the specification as a whole.